As a plug that is used in a portable music player, a plurality of standardized multi-pole plugs having two to four poles are provided in the related art. As types of the plugs, there are a standard type (a terminal having a diameter of 6.3 mm), a small type (referred to as a mini-plug and a terminal having a diameter of 3.5 mm), and an ultra-small type (referred to as a micro plug and a terminal having a diameter of 2.5 mm). Furthermore, the portable music player in recent years has a variety of functions and a plug with many pole numbers is also used since it is necessary to perform noise cancelling, to have a multifunctional remote control function, or the like.
The standard of the plug is established by Japanese Industrial Standards, Japan Electronics And Information Technology Industries Association (JEITA) Standard, and the like. A core rod electrode and a plurality of cylindrical electrodes extend and are exposed to a rear end side (an opposite end to a front end side that is inserted into a jack) of the plug. That is, in order to directly solder a wiring material to the electrode, an extension section of the electrode has a bamboo shoot structure.
For example, an antenna device that is configured of a plug having three electrodes for an antenna cable, an earphone cable, and an audio signal is disclosed in Patent Literature 1. In order to provide a relay section as a high-frequency signal blocking section between a cable for transmitting a stereo signal and the plug, the antenna device is configured such that a wiring substrate on which the relay section is mounted is connected to the plug. That is, a conductive pattern on the substrate and the electrode are connected to each other by cutting the substrate in a bamboo shoot shape.